1. Field of the Invention
The present invention relates to an optical lens and a light source module, and a street lamp having the same.
2. Description of the Related Art
Alight emitting diode (LED), a kind of a semiconductor light source, is a semiconductor device capable of emitting light having various colors through the recombination of electrons and electron holes in a junction portion between p-type and n-type semiconductors when current is applied thereto. Since the LED has a prolonged lifespan, low power consumption, excellent initial driving characteristics, a high vibration-resistance, or the like, as compared to a light source using a filament, the demand for LEDs has continuously increased, in particular, a group III nitride semiconductor LED capable of emitting light of a blue family of short wavelength region has been much in demand.
Recently there have been many attempts to substitute existing outdoor lighting apparatuses, such as street lamps and the like, with lighting apparatuses using LEDs. However, in case of an LED, light is only emitted in a specific direction, rather than being uniformly emitting in all directions, and an orientation angle thereof is generally about 120°. In comparison with existing outdoor lighting apparatuses emitting light in all directions, the light distribution characteristic of an LED are largely different therefrom, and thus, there is are limitations in using an LED in an outdoor lighting apparatus. Therefore, in the case of an optical lens and a light source module, and a street lamp using the same, a design solution in which light emitted from a light source is induced to have a desired orientation angle and dark spots are not formed therein is required.